Conveyors are used in a broad range of industries and applications to move packaged goods, assemblies, process byproducts, or any material from one place to another. A process designer will typically look for opportunities to use the force of gravity to accomplish product movement. Electric motors are commonly used when gravity cannot be employed or when the speed of a gravitational fall needs to be controlled.
Application Challenges
- Motor and Drive sizing
Conveyors requires a good deal of load and speed calculations, combined with actual testing to ensure proper size (power) requirements.
- Smooth product motion
Acceleration/Deceleration times combined with S-Curve “smoothing” characteristics need fine-tuning to ensure the product is not damaged and/or moved out of position for staging to subsequent processes.
- Rapid deceleration or downhill speed control of conveyors cause load regeneration in drives.
Care should be taken to ensure proper sizing of a drive’s dynamic braking package or regenerative converter, to prevent drive overvoltage faults.
- Electronic Gearing
Follow an external encoder to synchronize conveyor with other sections of the process
- Coordinate conveyor motion with external machine axes
- Reduce application development time
Applicable Products
Drives Products | Servo and Motion Products
| Drives Products | Features | Benefits |
| Simple, compact, reliable, low cost solution for lower horsepower ranges. (Up to 5 hp) | Offers flexibility of design in modular conveyor arrangements for small horsepower applications. |
| V74X provides NEMA 4X enclosure type | "Washdown" environmental rating for direct mounting to food processing conveyors |
| V7N provides embedded DeviceNet communications | (ODVA) communication for control or monitoring of many drive/conveyors |
| 3-Level PWM voltage output | Minimizes peak voltages at motor to extend motor and bearing life in long cable runs. |
| Pulse Train I/O for speed control | Control speed of parallel or series conveyors by use of Pulse Train I/O function in the drive. Eliminates the need for complex pulse to analog converter. |
Momentary Powerloss Ride-thru
Automatic Fault Restart | The Momentary Powerloss Ride-thru and Fault Restart functions allow the drive to continue operation without the need for attended restart. |
| Fully adjustable S-Curve and Accel/Decel rates | Smooth starting and stopping is achieved through the drives Accel/Decel and S-Curve characteristics. |
| Torque Limit | Torque Limit protects the load and other machinery from excessive torque that may occur when the load fluctuates or seizes. |
| Zero-Servo Function | The Zero Servo Function in the Closed Loop Flux Vector Mode makes a mechanical brake unnecessary for tilt-tray and certain incline conveyors that require a mechanical brake to stop. |
| Torque Control in Closed loop Flux Vector Mode and Speed Droop control in V/f Control Mode | Operating two or more conveyor motors in series. The load may shift off between motors. The drive allows for load sharing by using Torque Control or Droop Control. |
| Line regenerative products | Line regenerative units can be a cost effective option to resistors when sizing high duty braking circuits for downhill or rapid decel applications. |
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| Servo and Motion Products | Features | Benefits |
| Easy-to-use ladder logic programming | Reduced application development time |
| Electronic gear to unlimited number of masters | Coordinate conveyor motion with other machine axes |
| S-curve acceleration and deceleration | Smoother acceleration and deceleration to protect product |
| Three available slots for additional modules | Easily integrate with a variety of communication options |
| Simple text-based language | Fastest time from box to motion |
| Up to four axes of control | Control all machine axes from a central location for easy coordination |
| Electronically gear between multiple axes | Coordinate with other controlled axes or external encoders |
| Extended Ethernet I/O available | Improved connectivity and flexibility |
| Machine control capabilities in single-axis controller | Reduce third-party devices by combining machine control with motion control |
| Electronic gearing from external encoder | Coordinate with external axes critical to machine performance |
| Integrated DeviceNet communications | Integrate with a variety of manufacturers |
| Simple text-based language | Increased application development efficiency |
| Connect up to eight SMC-3010 controllers for distributed control | Control multiple axes from a centralized controller, ideal for identical single-axis applications |
| Extended Ethernet I/O | Improved process monitoring |
| Up to 128 selectable program steps | Large number of programming routines can be created |
| Incremental, Absolute, Infinite move types | Variety of move types allow for flexible sequences |
| Five programmable outputs - On, Off, Zone, Maintained settings | Integrate control with other devices |
| Precision control | High resolution serial encoder eliminates position error caused by electrical noise |
| Integrated brake motor option available | Maintain position for inclined loads |
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Application Details
Airports, mines, cement plants, distribution facilities, assembly, and food processing plants all utilize conveyors. Conveyors are typically constant torque loads, meaning the required torque to drive a conveyor is independent of speed. A fixed amount of torque is also required to overcome the frictional, or machine drag, portion of the total load. Conveyors can have nominal amounts of friction and machine inertia for which to compensate.
Yaskawa's motion control products offer a variety of solutions for conveyors. Single-axis options are available for integrating to PLCs or multi-axis machine controllers capable of integrating multiple steps within the machine process to centralize control of the application. Utilizing the built-in functionality of these controllers provides the highest performance through synchronized, coordinated motion control, capable of easily integrating to third-party devices.
For Yaskawa drive products, the heaviest conveyor load needs to be a consideration when sizing drives and motors for conveyors. Quite often, speed, load and Accel/Decel testing is performed to determine proper drive and motor sizing for conveyors. Speed deviation may also be a consideration when selecting conveyor-driving components. The tolerable speed deviation is a concern if heavy objects are dropped on to the moving conveyor.
If product orientation and/or position are critical to the application, then fine-tuning acceleration, fine-tuning acceleration rates and s-curve smoothing help to achieve product movement while keeping transported products stable. This is key when transferring a product from one automated process to another.
Downhill or rapid deceleration of conveyors may require braking provisions to avoid overvoltage faults on the drive’s DC bus. When decelerating large loads, conveyor friction is an advantage that allows for light to medium braking resistor circuits. When operating a downhill conveyor, however, the motor typically will regenerate power on a continual basis. In these cases, it can be advantageous to use an RC5 or DC5 to allow this power to pass back to the line.
Additional Information
The pdf contains the same information as the web, but in some cases may contain more and should be used if a printed version is required.
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